学生管理系统--java+mysql-Toy模板网

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学生管理系统

简介

练习：完成学生信息的增删查改（根据id），项目进行了三层架构进行创建。
学生管理系统mysql,数据库,java,idea,后端
pojo层，dao层，service层，utils层，程序入口；

1.pojo层

实体层数据库在项目中的类
Entity层是实体层，也就是所谓的model，也称为pojo层，是数据库在项目中的类，该文件包含实体类的属性和对应属性的set、get方法；
pojo内的student类，主要是与数据库中相应的表进行对应，字段类型需一一对应。

package student.pojo;
/**
 * @description: TODO
 * @date 2023/7/15 9:14
 */
public class Student {
    private int id;
    private String name;
    private String className;
    private String score;

    public Student() {
    }

    public Student(int id, String name, String className, String score) {
        this.id = id;
        this.name = name;
        this.className = className;
        this.score = score;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getClassName() {
        return className;
    }

    public void setClassName(String className) {
        this.className = className;
    }

    public String getScore() {
        return score;
    }

    public void setScore(String score) {
        this.score = score;
    }

    @Override
    public String toString() {
        return
                "学号：" + id +"\t" +
                " 姓名：" + name + '\t' +
                "班级:" + className + '\t' +
                "成绩：" + score + '\t' ;
    }
}

2.dao层

持久层主要与数据库进行交互
DAO层=mapper层，现在用Mybatis逆向工程生成的mapper层，其实就是dao层。DAO层会调用entity层，DAO中会定义实际使用到的方法，比如增删改查。DAO 层的数据源和数据库连接的参数都是在配置文件中进行配置的，配置文件一般在同层的XML文件夹中。数据持久化操作就是指，把数据放到持久化的介质中，同时提供增删改查操作。

package student.dao;

import student.pojo.Student;

public interface StudentDao {
    /**
     *  根据id查询信息
     * @param id
     */
    Student findById(int id);

    /**
     * 新增学生信息
     * @param student
     * @return
     */
    void addStudent(Student student);

    /**
     * 根据id删除信息
     * @param id
     */
    void deleteStudent(int id);

    /**
     * 更新学生信息
     * @param student
     */
    void updateStudent(Student student);
}

实现类impl
dao接口中方法的具体实现

package student.dao.imp;

import student.dao.StudentDao;
import student.pojo.Student;
import student.utils.OperationUtils;

/**
 * @description: TODO
 * @date 2023/7/15 10:33
 */
public class StudentDaoImp implements StudentDao {
    @Override
    public Student findById(int id) {
        Student student = OperationUtils.findById(id);
        return student;
    }

    @Override
    public void addStudent(Student student) {
        OperationUtils.addStudent(student);
    }

    @Override
    public void deleteStudent(int id) {
        OperationUtils.deleteStudent(id);
    }

    @Override
    public void updateStudent(Student student) {
        OperationUtils.updateStudent(student);
    }
}

3.service层

业务层控制业务
Service层主要负责业务模块的逻辑应用设计。先设计放接口的类，再创建实现的类，然后在配置文件中进行配置其实现的关联。service层调用dao层接口，接收dao层返回的数据，完成项目的基本功能设计。
封装Service层的业务逻辑有利于业务逻辑的独立性和重复利用性。

public interface StudentService {

    Student findById(int id);
    void addStudent(Student student);
    void deleteStudent(int id);
    void updateStudent(Student student);

}

package student.service.imp;

import student.dao.StudentDao;
import student.dao.imp.StudentDaoImp;
import student.pojo.Student;
import student.service.StudentService;

/**
 * @description: TODO
 * @date 2023/7/15 10:44
 */
public class StudentServiceImp implements StudentService {
    StudentDao studentDaoImp = new StudentDaoImp();
    @Override
    public Student findById(int id) {
        Student student = studentDaoImp.findById(id);
        return student;
    }

    @Override
    public void addStudent(Student student) {
        studentDaoImp.addStudent(student);
    }

    @Override
    public void deleteStudent(int id) {
        studentDaoImp.deleteStudent(id);
    }

    @Override
    public void updateStudent(Student student) {
        studentDaoImp.updateStudent(student);
    }
}

4.utils工具类

完成数据库连接，具体的增删查改方法等，提高代码的复用率。

4.1数据库连接工具

这里使用jbdc，properties进行数据库连接（具体jdbc知识之前的博客有）

driver = com.mysql.cj.jdbc.Driver
url = jdbc:mysql://localhost:3306/student_db?useUnicode=true&characterEncoding=utf8&useSSL=false&serverTimezone=UTC
username = root
password = 123456

这里将关闭和连接分成两个方法，方便调用释放资源

package student.utils;

import java.io.FileInputStream;
import java.io.IOException;
import java.sql.*;
import java.util.Properties;
/**
 * @description: TODO
 * @date 2023/7/14 20:07
 */
public class JdbcUtils {
    private static String url;
    private static String driver;
    private static String username;
    private static String password;

    static {
        Properties properties = new Properties();
        try {
            properties.load(new FileInputStream("src\\db.properties"));
             url = properties.getProperty("url");
             driver = properties.getProperty("driver");
             username = properties.getProperty("username");
             password = properties.getProperty("password");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    /**
     * 建立数据库连接
     * @return
     */
    public static Connection getConnection() {
        try {
            return DriverManager.getConnection(url,username,password);
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }
    }
    /**
     * 关闭数据库连接，释放资源
     */
    public static void close(Statement statement, ResultSet resultSet,Connection connection){
        try {
            if (statement != null){
                statement.close();
            }
            if (resultSet != null){
                resultSet.close();
            }
            if (connection != null) {
                connection.close();
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

4.2 OperationUtils具体的增删查改方法

package student.utils;

import student.pojo.Student;

import java.sql.*;

/**
 * @description: TODO
 * @date 2023/7/15 9:13
 * 数据库的增删查改
 */
public class OperationUtils {
    private Student student = new Student();

    /**
     * 查询
     * @param id
     * @return 根据id查找学生信息
     */
    public static Student findById(int id){
        Student student = null;
        try {
            Connection connection = JdbcUtils.getConnection();
            String sql = "select * from student where id = ?";
            PreparedStatement statement = connection.prepareStatement(sql);
            statement.setInt(1, id);
            ResultSet resultSet = statement.executeQuery();
            while (resultSet.next()) {
                id = resultSet.getInt(1);
                String name = resultSet.getString(2);
                String classname = resultSet.getString(3);
                String score = resultSet.getString(4);

                 student = new Student(id, name, classname, score);

                 //JdbcUtils.close(statement,resultSet,connection);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
       return student;
    }

    /**
     * 添加信息
     * @return
     */
    public static void addStudent(Student student){

        Connection connection = JdbcUtils.getConnection();
        String sql = "insert into student values(?,?,?,?)";
        try {
            PreparedStatement statement = connection.prepareStatement(sql);
            statement.setInt(1, student.getId());
            statement.setString(2, student.getName());
            statement.setString(3, student.getClassName());
            statement.setString(4, student.getScore());

           int i = statement.executeUpdate();
             if (i>0){
                 System.out.println("数据添加成功！");
             }
             JdbcUtils.close(statement,null,connection);
        } catch (SQLException e) {
            e.printStackTrace();
        }

    }

    /**
     * 根据id删除学生信息
     * @param id
     */
    public static void deleteStudent(int id){
        Connection connection = JdbcUtils.getConnection();
        String sql = "delete from student where id = ?";
        try {
            PreparedStatement statement = connection.prepareStatement(sql);
            statement.setInt(1,id);
            int i = statement.executeUpdate();
            if (i>0){
                System.out.println("删除成功！");
            }else {
                System.out.println("删除失败");
            }
            JdbcUtils.close(statement, null, connection);
        } catch (SQLException e) {
            e.printStackTrace();
        }

    }

    /**
     * 更新
     * @param student
     */
    public static void updateStudent(Student student){
        Connection connection = JdbcUtils.getConnection();
        String sql = "update student set name = ?,className = ?,score =? where id = ?";
        try {
            PreparedStatement statement = connection.prepareStatement(sql);
            statement.setString(1, student.getName());
            statement.setString(2, student.getClassName());
            statement.setString(3, student.getScore());
            statement.setInt(4,student.getId());

            int i = statement.executeUpdate();
            if (i>0) {
                System.out.println("更新成功");
            }
            JdbcUtils.close(statement,null,connection);
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

4.3 Menu主菜单

switch语句进行选择

package student.utils;

import student.dao.StudentDao;
import student.dao.imp.*;
import student.pojo.Student;

import java.util.Scanner;

/**
 * @description: TODO
 * @date 2023/7/15 10:49
 */
@SuppressWarnings("all")
public class Menu {
    private static Scanner scanner = new Scanner(System.in);
    public static void menuStudent() {
        while (true) {
            OperationMenu.start();
            int i = scanner.nextInt();
        switch (i) {
            case 1:
                OperationMenu.find();
                break;
            case 2:
              OperationMenu.update();
                break;
            case 3:
                OperationMenu.add();
                break;
            case 4:
               OperationMenu.delete();
                break;
            case 5:
                System.exit(0);
       		 }
    	}
	}
}

4.4 OperationMenu每一个case里的具体操作

package student.utils;

import student.dao.StudentDao;
import student.dao.imp.StudentDaoImp;
import student.pojo.Student;
import student.service.StudentService;
import student.service.imp.StudentServiceImp;

import java.util.Scanner;

/**
 * @description: TODO
 * @date 2023/7/15 14:28
 */
public class OperationMenu {
   private static StudentDao studentDaoImp = new StudentDaoImp();
   private static StudentService studentService = new StudentServiceImp();
   private static Scanner scanner = new Scanner(System.in);
    public static void find(){
        System.out.print("输入要查询学生的学号：");
        int id = scanner.nextInt();
        Student student = studentService.findById(id);
        System.out.println(student);
    }

    public static void  update() {
        System.out.println("请输入要修改的信息");
        System.out.println("请输入要修改学生的学号：");
        int updateid = scanner.nextInt();
        System.out.println("请输入修改后的姓名：");
        String name = scanner.next();
        System.out.println("请输入修改后的班级：");
        String classname = scanner.next();
        System.out.println("请输入要修改的成绩：");
        String score = scanner.next();
        Student student = new Student();
        student.setId(updateid);
        student.setName(name);
        student.setScore(score);
        student.setClassName(classname);
        studentService.updateStudent(student);
    }

    public static void add(){
        System.out.println("请输入要增加的学生信息：");
        System.out.println("输入学生学号：");
        int addid = scanner.nextInt();
        System.out.println("输入学生姓名：");
        String addname = scanner.next();
        System.out.println("输入学生班级：");
        String addclass = scanner.next();
        System.out.println("输入学生成绩：");
        String addscore = scanner.next();
        Student newstudent = new Student(addid,addname,addclass,addscore);
        studentService.addStudent(newstudent);
    }
    public static void delete(){
        System.out.println("请输入要删除的学生学号");
        int delid = scanner.nextInt();
        studentService.deleteStudent(delid);

    }
    public static void start(){
        System.out.println("=============欢迎登录学生管理系统=============");
        System.out.println("1.查询学生信息");
        System.out.println("2.修改学生信息");
        System.out.println("3.增加学生信息");
        System.out.println("4.删除学生信息");
        System.out.println("5.退出");
        System.out.println("选择功能：");

    }
}

4.5 AppMain程序入口

public class AppMain {
    public static void main(String[] args) {
        Menu.menuStudent();
    }
}

5.实现效果

学生管理系统mysql,数据库,java,idea,后端文章来源地址https://www.toymoban.com/news/detail-598742.html

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学生管理系统--java+mysql